The odorants contributing to the characteristic aroma of matcha were investigated by analysis of the headspace samples and the volatile fractions prepared by a combination of solvent extraction and the SAFE techniques using three matcha powders of different grades (high, medium, and low). Gas chromatography-olfactometry of the headspace samples (GCO-H) and aroma extract dilution analysis (AEDA) applied to the volatile fractions revealed 16 (FD factor ≥1) and 39 (FD factor ≥4) odor-active peaks, respectively. Among them, 14 and 37 of the odorants, most of which were newly detected in matcha, were identified or tentatively identified by GC-MS and GC-O, respectively. By comparing the perceived odorants of three matcha powders, it was revealed that eight compounds with sweet, green, metallic, and floral notes showed high flavor dilution (FD) factors irrespective of the grades. In addition, some odorants were suggested to influence the characteristic aroma of each grade. Furthermore, trans-4,5-epoxy-(E)-2-decenal, one of the potent odorants of matcha, was revealed to exist as a racemic mixture in matcha. This result suggested that trans-4,5-epoxy-(E)-2-decenal is formed by a nonenzymatic reaction in matcha, different from that in black tea, and that the unique manufacturing process of matcha has a close connection with its formation.

To clarify the characteristic sweet aroma of Wagyu (Japanese Black Cattle), aroma extraction dilution analysis (AEDA) was applied to the volatile fractions of Wagyu and Australia beefs. Some 20 odor-active peaks were detected, and 17 odorants were identified or tentatively identified. Among the perceived odorants, most of them were newly identified from the Wagyu beef. The main constituents of the potent odorants were aldehydes and ketones, which are known as the degradation products of polyunsaturated fatty acids that were significantly included in the lipids of the Wagyu. In addition, the most potent odorant was trans-4,5-epoxy-(E)-2-decenal, which is known to be the oxidation product of polyunsaturated acids, such as linoleic acid and arachidonic acid, that were significantly included in the lipids of the Wagyu. Accordingly, these findings strongly suggested that the kind of fatty acid constituting lipids of the Wagyu plays an important role in the formation of the characteristic aroma of the Wagyu beef.